Skip to main content

Full text of "Text Book Of Mechanical Engineering"

See other formats


Turning Quarter Bends.

shave, and tried from time to time by applying the template ;D ;
in fact, working in wood much as the moulder works in loam at
Fig. 25 in the last chapter.

A still more handy way of making quarter bends is to turn a
built-up ring of semi-circular section on the face plate of the lathe,
Fig. 60, and afterwards to cut into four equal pieces, as shewn in
dotted lines, Fig. 6yA. On removing and placing back to back,


F,Wj.  67 cu.

we have clearly two complete patterns, and flanges may be added
as necessary.

If a single bent pipe  of whatever form of bend (so that it be
in one plane)  is required, it should be moulded as at Figs. 25,
26, or 26a; the pattern maker will supply the necessary tem-
plates. Curiously shaped pipes, of varying bore, may have a
core box only ; the outer pattern being built by the moulder, who
lays thickness pieces on the core, smoothing off with loam ;
after taking an impression, the thickness pieces are removed (see
description to Figs. 25 and 26).

Joints.  Many other methods of jointing, besides halving and
rabbeting, are, of course, used, such as dovetailing and tenoning,
but we must content ourselves with a general notion of the making
of a pattern.

Varnishing.  When finished and sand-papered, the pattern